| Description |
The ShowMessageFmt procedure provides 'C' like formatting of multiple of simple data types into a string that is displayed in a single. It provides very precise control over this formatting.
The Formatting parameter defines how the Data array is manipulated into the displayed string.
The dialog has an OK button to allow the user to register the message and close the dialog.
The Formatting string can comprise a mix of ordinary characters (that are passed unchanged to the result string), and data formatting characters. This formatting is best explained by the example code.
In simple terms, each data formatting substring starts with a % and ends with a data type indicator :
| d | = Decimal (integer) |
| e | = Scientific |
| f | = Fixed |
| g | = General |
| m | = Money |
| n | = Number (floating) |
| p | = Pointer |
| s | = String |
| u | = Unsigned decimal |
| x | = Hexadecimal |
The general format of each formatting substring is as follows:
%[Index:][-][Width][.Precision]Type
where the square brackets refer to optional parameters, and the : . - characters are literals, the first 2 of which are used to identify two of the optional arguments.
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| Related commands |
| InputBox |
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Display a dialog that asks for user text input, with default |
| InputQuery |
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Display a dialog that asks for user text input |
| MessageDlg |
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Displays a message, symbol, and selectable buttons |
| MessageDlgPos |
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Displays a message plus buttons at a given screen position |
| PromptForFileName |
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Shows a dialog allowing the user to select a file |
| ShowMessage |
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Display a string in a simple dialog with an OK button |
| ShowMessagePos |
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Display a string in a simple dialog at a given screen position |
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| Example code : Showing all of the formatting data types |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
text : string;
begin
// Just 1 data item
ShowMessageFmt('%s', ['Hello']);
// A mix of literal text and a data item
ShowMessageFmt('String = %s', ['Hello']);
ShowMessage('');
// Examples of each of the data types
ShowMessageFmt('Decimal = %d', [-123]);
ShowMessageFmt('Exponent = %e', [12345.678]);
ShowMessageFmt('Fixed = %f', [12345.678]);
ShowMessageFmt('General = %g', [12345.678]);
ShowMessageFmt('Number = %n', [12345.678]);
ShowMessageFmt('Money = %m', [12345.678]);
ShowMessageFmt('Pointer = %p', [addr(text)]);
ShowMessageFmt('String = %s', ['Hello']);
ShowMessageFmt('Unsigned decimal = %u', [123]);
ShowMessageFmt('Hexadecimal = %x', [140]);
end;
end.
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| Hide full unit code |
Hello
String = Hello
Decimal = -123
Exponent = 1.23456780000000E+004
Fixed = 12345.68
General = 12345.678
Number = 12,345,68
Money = ?12,345.68
Pointer = 0069FC90
String = Hello
Unsigned decimal = 123
Hexadecimal = 8C
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| Example code : Using the index, width and precision values |
begin
// The width value dictates the output size
// with blank padding to the left
// Note the <> characters are added to show formatting
ShowMessageFmt('Padded decimal = <%7d>', [1234]);
// With the '-' operator, the data is left justified
ShowMessageFmt('Justified decimal = <%-7d>', [1234]);
// The precision value forces 0 padding to the desired size
ShowMessageFmt('0 padded decimal = <%.6d>', [1234]);
// A combination of width and precision
// Note that width value precedes the precision value
ShowMessageFmt('Width + precision = <%8.6d>', [1234]);
// The index value allows the next value in the data array
// to be changed
ShowMessageFmt('Reposition after 3 strings = %s %s %s %1:s %s',
['Zero', 'One', 'Two', 'Three']);
// One or more of the values may be provided by the
// data array itself. Note that testing has shown that an *
// for the width parameter can yield EConvertError.
ShowMessageFmt('In line = <%10.4d>', [1234]);
ShowMessageFmt('Part data driven = <%*.4d>', [10, 1234]);
ShowMessageFmt('Data driven = <%*.*d>', [10, 4, 1234]);
end;
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| Show full unit code |
Padded decimal = < 1234>
Justified decimal = <1234 >
0 padded decimal = <001234>
Width + precision = < 001234>
Reposition after 3 strings = Zero One Two One Two
In line = < 1234>
Part data driven = < 1234>
Data driven = < 1234>
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